S. Sundaram, J. McCloy, B. Riley, M. Murphy, H. Qiao, C. Windisch Jr., E. Walter, J. Crum, R. Golovchak, and O. Shpotyuk.
Journal of American Ceramic Society, vol. 95, 2011, p. 1048–1055.
Gamma radiation is known to induce changes in physical, optical, and structural properties in chalcogenide glasses, but previous research has focused on As2S3 and families of glasses containing Ge. For the first time, we present composition and dose dependent data on the As–S binary glass series. Binary AsxS100-x (x = 30, 33, 36, 40, and 42) glasses were irradiated with gamma radiation using a 60Co source at 2.8 Gy/s to accumulated doses of 1, 2, 3, and 4 MGy. The irradiated samples were characterized at each dose level for density, refractive index, X-ray diffraction (XRD), and Raman spectrum. We report an initial increase in density followed by a decrease as a function of dose that contradicts the expected compositional dependence of molar volume of these glasses. This unusual behavior is explained based on microvoid formation and nanoscale phase-separation induced by the irradiation. XRD, Raman, and electron spin resonance data provide supporting evidence, underscoring the importance of optimally- or overly constrained structures for stability under irradiation.